Accompanied by the opening China society, people's living standard is to be elevated. To meet the requirements for pursuing a better life quality, massagers are in demand by some people to diminish pains; especially, back aches. In recent years, kinds of massagers are developed, such as head massager, foot massager, electromagnetic wave massager, and back massager etc. At present time, the back massager in usual is equipped with an electromagnetic hammer fixed to the back plate, which is dominated by running a programmed course to control the vibration of the electromagnetic hammer; therefore, a press, squeeze, or pinch, is exerted to the aching with fatigue body portion. Or a single vibrator is harmonized with a succession of continually pulsed vibrations to massage the body portion. However, these massagers are not only designed in a limited massaging portion, but the product expectation is also hardly met as desired. It is not expected that a conventional massager can be used to imitate and substitute for a professional massagist.